As a result of the divestiture of AT&T, local exchange carriers now bill interconnect carriers access charges for customer call attempts originating from the local exchange carrier network to the interconnect carrier and for the time the customer is connected to the interconnect carrier. In addition, the local exchange carriers also bill the interconnect carrier for the time completed calls terminate on the local exchange carrier network. These charges are also based on the distance between the local exchange carrier end office and a point of presence in the interconnect carrier network such as a toll interconnect carrier switching office. Charges may also differ based on the type of service or whether the call is, for example, intra/interstate, inter/intra LATA, international, or special service such as "800" type calls.
There are a number of prior art methods for recording information on trunk usage and determining access charges. For equal access local exchange carrier offices, one technique is to record automatic message accounting (AMA) records for each originating call attempt and terminating call completion. The cost of telephone office equipment to generate these AMA records and the cost of off-line processing for the generated records is enormous and not cost effective. Per call records are not required to determine access charges and are unnecessary particularly when only those AMA records associated with completed calls are necessary for charging the customer. With non equal access local exchange carrier telephone offices, AMA records for completed calls and traffic usage measurements are used to approximate originating call attempts and terminating call completions. Furthermore, time charges are likewise approximated based on the AMA call completion records and traffic usage measurements. A problem with this approximation technique is the inherent error for approximated call attempts, the type of call, usage time, and the number of terminating completions. With billions of dollars being paid from just AT&T to local exchange carriers, approximation errors can easily result in several hundreds of millions of dollars in excess access charges.
Present methods for verifying access charges levied by the local exchange carriers include various types of sampling techniques. For instance, the interconnect carrier may purchase a sample of all of the AMA records generated by the local exchange carrier to determine originating call attempts, type of service, trunk usage, and terminating call completions. This sample is only from AMA call completion records. Again, at best, this sampling technique has inherent errors which again can produce hundreds of millions of dollars in excess access charges. Furthermore, the cost of the sample from the local exchange carrier and the processing of these call details has resulted in enormous processing fees.